The present invention relates to improved paper web winders, and more particularly to a two drum winder wherein a roll is wound on a core and supported on driven drums with a rider roll on the roll being wound.
Winding a roll of paper on a core is a conventional operation in a paper making machine wherein the freshly made web is wound on a roll and this process is also used in converting operation wherein previously wound rolls are unwound for processing including slitting, coating and the like, and then rewound to a roll of finished size. In a paper making operation, the winding roll must be driven at the speed that the paper making machine is operated which becomes relatively high, and in a converting operation for speed of production, it is imperative that the rolls be wound at a relatively high speed. Speeds of 3,000 to 6,000 feet per minute are common, and the rolls which are wound must rotate at that peripheral speed, and as they build up in size, they possess a great deal of kinetic energy and become difficult to control.
A conventional winding structure which is used of one type is a two drum winder wherein parallel drums driven in rotation in the same direction receive a core between them with the traveling web being wound onto the core. The coaction between the supporting drums and the roll being wound, of course, changes as the roll builds up in size because the angle of contact or angle of support between the supporting drums and the wound roll changes as the roll changes in diameter, and of course, the surface pressure changes as the roll increases in size and weight. It is conventional to attempt to control the surface pressure to a degree by using a rider roll for applying a downward pressure on the roll being wound at the beginning of operation and relieving this pressure as the weight of the roll increases and at some point in the size of the roll being wound applying an upward lift on the core. The object of control of the roll being wound is to control the surface force between the winding drum and the roll being wound inasmuch as this surface force controls the tension with which the web is wound on the roll. It is, therefore, important not only to control this surface force but to maintain it constant. The constant pressure and constant effect of the drum on the roll is threatened by vibration or bounce of the roll on the drums. This bounce may occur as a straight up and down vibration of the roll, or it may occur as a rocking vibration wherein the winding roll shifts its weight from drum to drum in a rocking motion. This rocking vibration is the most difficult mode to control. It is desirable to eliminate the rocking motion, and attempts have been made to stabilize the position of the roll, and one way this can be done is to attempt to control the vibrational frequency of the bounce or rocking vibration of the roll.
It is accordingly an object of the present invention to provide an improved drum winder which is capable of winding a more uniform roll and which eliminates the undesirable effect of vibration, bounce and rocking which occurs on winders heretofore available.
A further object of the invention is to provide a two drum winder wherein the structure has additional means for controlling the forces between the drums in the wound roll thereby controlling effects of bouncing or vibration.
A further object of the invention is to provide a two drum winder wherein it is possible to change the vibration or bounce frequency and raise these frequencies outside of the speed range of the winder so that the winding of the roll will become more stable, and the web mounted thereon will be of uniform tightness throughout the circumference and uneven soft and hard spots will not occur around the circumference of the roll.
In reference to a two drum winder, it is generally meant a structure wherein two parallel supporting drums are provided which are driven in rotation for supporting a roll being wound thereon, but the structure is to include different modifications of the two drum winder and, for example, is to include a structure such as that shown in U.S. Pat. No. 3,869,095, Diltz, issued Mar. 4, 1975 wherein three drums are provided to provide two locations for winding a roll.
Other objects, advantages and features as well as equivalent structures and methods which are intended to be covered herein will become more apparent with the teaching of the principles of the present invention in connection with the disclosure of the preferred embodiment in the specification, claims and drawing, in which: